Apparatus and process for optimizing work from a smart material actuator product

ABSTRACT

An apparatus and process for pre-loading an electrically stimulated smart material actuator product to obtain maximum work from the actuator. When a smart material actuator is optimally pre-loaded certain desirable characteristics become apparent, such as work, operational frequency, hysteresis, repeatability, and overall accuracy. When used in conjunction with a mechanically leveraged actuator structure the smart material actuator can be used to its greatest potential. Since the mechanically leveraged actuator can be based on the maximum work provided by the smart material actuator, certain attributes such as the force, and displacement of total system can be adjusted without loss to system efficiency. Pre-loading methods and a determination of the optimal pre-load force are disclosed. Each smart material actuator type has a unique work curve. In the design of an actuator assembly, the process of optimizing uses the unique work curve to optimize the design for the requirements of the particular application. The unique work curve is used by finding the place where the smart material actuator is capable of providing the most work in order to set the optimum pre-load point accordingly. Different mechanical pre-load techniques are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of provisional patentapplication Ser. No. 60/460,548 filed on Apr. 4, 2003, which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to an actuator assembly,and more specifically relates to optimization of work from a supportstructure moveable in response to electrical activation of a smartmaterial actuator.

BACKGROUND OF THE INVENTION

[0003] The invention is based on actuator technologies being developedfor a wide range of applications including industry. One component usedin this type of actuator is an electrically stimulated smart materialactuator. These smart material actuators when electrically stimulatedchange shape. This shape change can be designed such that one axispredominantly changes. As this axis changes dimension it is magnified bya lever integral to the main support structure creating an actuator witha useful amount of displacement. This displacement is useful forgeneral-purpose industrial applications such as grippers, linear motors,and consumer applications such as speakers. Presently, electromechanicaldevices are used such as motors, solenoids, and voice coils. In generalthese devices encompass many shortcomings, i.e. they are large andheavy, consume high amounts of power, and do not work in a proportionalmanner.

[0004] Various types of smart material actuators are known to thoseskilled in the art. Traditionally the smart material actuator is usedtwo ways, first direct acting and second in a mechanically leveragedsystem. Most of these systems have some sort of mechanical pre-load.This pre-load has largely been used to capture the smart materialactuator within the main structure. It has not generally been recognizedthat the pre-load force applied to the smart material actuator canaffect the performance of the actuator.

[0005] In such known devices, when the smart material actuator iselectrically activated, the geometry of the device expands predominantlyalong a predetermined axis. When the smart material device isdeactivated, the geometry of the device contracts predominantly alongthe predetermined axis. This expansion and contraction of the smartmaterial can be used to operate an apparatus, e.g. to open or close agripper or vibrate a speaker cone.

SUMMARY OF THE INVENTION

[0006] Heretofore, it has not generally been recognized that individualsmart material actuator types have an optimal pre-load and/or range,where the smart material actuator provides optimal work. For the purposeof this discussion, work is defined as the force/displacement product,given that input energy is relatively constant. When using the smartmaterial actuator within its peak work area, the smart material actuatoris at its peak efficiency. Since the optimal pre-load for a large smartactuator can be greater than 100 pounds, the method used to create thepre-load force is critical.

[0007] The smart material can be disposed between a main supportstructure with an integral hinge, spring, and at least one arm in acurvilinear path around the main support structure. The optimal pre-loadforce can be designed into the main support structure and provide forpre-load adjustment. The smart material actuator in most knownconfigurations provides little opportunity to select different hingeaxis locations, high pre-load forces and/or structural configurations tooptimize performance. These objectives have been a difficult combinationto achieve with inexpensive materials for high volume commercializationof smart material actuators.

[0008] The present invention optimizes the performance of a smartmaterial actuator, providing performance and flexibility never possiblebefore. The present invention provides a process for determining optimalpreload for a mechanically leveraged smart material actuator.Preferably, a smart material actuator can be captured in place between arigid non-flexing portion and force transfer member, by way of exampleand not limitation, machined from a single block of material withintegral preload mechanism. The apparatus can include a support having arigid non-flexing portion, at least one arm portion extending forwardfrom the rigid portion, at least one surface on each pivotable arm formovement relative to the support structure, and a force transfer memberoperably positioned with respect to the at least one arm. A rigidnon-flexing portion can support the preload mechanism. An actuator canbe operably engaged between the preload mechanism and the force transfermember to drive the force transfer member in movement along a fixed pathcausing the at least one pivotable arm portion to pivot in response toan electrical activation. The support, pivotable arm, and force transfermember of the structure can be designed to be rigid, non-flexingportions of a monolithic structure interconnected by flexible hingeportions allowing the at least one arm to move relative to the remainingsupport structure. Any unplanned flexing can reduce the effective lifeof the mechanism, and reduce the amount of force transferred through thehinge axis to the at least one pivot arm. The reduction in force limitsthe displacement and force of the pivoting arm. The selection of thehinge axis location and corresponding structural configuration can allowsubstantial capability to optimize the performance and size of theapparatus for the particular application.

[0009] The smart material can be preloaded with a force when installedin the support element. For example, the smart material actuator can beclamped within the support structure with an adjustable screw supportingone end allowing the optimal force preloading. An adjustable screwconfiguration is easy to use and allows for a large adjustability.Depending on the preload force an acceptable screw configuration can bedesigned. Preloading the smart material actuator in a suitable fashioncan contribute to the maximum efficiency of the force transfer duringthe actuation, and allows fine-tuning of the initial position of theapparatus prior to the actuation of the smart material element. Certainsmart materials have an optimal preload, i.e. the actuator performs thelargest amount of work at that preload. Preload can also ensure that thesmart material actuator maintains contact with the apparatus at oppositeends throughout the range of expansion and contraction. The use of athreaded adjustment screw for preloading enables assembly withoutrequiring adhesives or other means of securely connecting the smartmaterial actuator at opposite ends to the apparatus, and avoids thepossibility of damaging tension or torsional movements on the smartmaterial actuator. The threaded adjustment screw allows simplecompensation for dimensional variations in the smart material actuatorduring assembly to the support. The present invention optimizes thepreload such that the smart material actuator can provide the optimalwork, as well as several preload mechanisms suitable for the apparatus.

[0010] Other applications of the present invention will become apparentto those skilled in the art when the following description of the bestmode contemplated for practicing the invention is read in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The description herein makes reference to the accompanyingdrawings wherein like reference numerals refer to like parts throughoutthe several views, and wherein:

[0012]FIG. 1 is a graph illustrating the performance of a smart materialactuator showing deflection versus force for both energized andde-energized states;

[0013]FIG. 2 is a graph illustrating the product of displacement timesblocking force versus force for the values shown in FIG. 1;

[0014]FIG. 3 is a graph illustrating performance of a smart materialactuator at a predetermined pre-load;

[0015]FIG. 4 is a perspective view of one embodiment of the presentinvention;

[0016]FIG. 5a is a perspective view of another embodiment of the presentinvention;

[0017]FIG. 5b is a detail view of FIG. 5a in accordance with the presentinvention;

[0018]FIG. 6a is a side view of another embodiment of the presentinvention;

[0019]FIG. 6b is a detail view of FIG. 8a in accordance with the presentinvention;

[0020]FIG. 7a is a cutaway perspective view of another embodiment of thepresent invention;

[0021]FIG. 7b is a detail view of FIG. 8a in accordance with the presentinvention;

[0022]FIG. 8 is a cutaway perspective view of another embodiment of thepresent invention;

[0023]FIG. 9 is a cutaway perspective view of another embodiment of thepresent invention;

[0024]FIG. 10 is a side view of another embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] Referring now to FIG. 1, a displacement-force graph for a smartmaterial actuator both energized and de-energized is depicted. For thede-energized curve the smart material actuator was shorted orde-energized. The de-energized curve was taken starting at a force of 10and an ending force of 100. The compressive deflection was noted atvarious points between the forces of 10 to 100.

[0026] These points were then plotted as the line on the graph in FIG. 1with diamonds to indicate the series. For the energized curve the smartmaterial actuator was connected to a power supply delivering the correctactuation voltage. The energized curve was taken starting at a force of10 and an ending force of 100. These points were then plotted as theline on the graph in FIG. 1 with squares to indicate the series. Fromthe graph it can be seen that the energized and de-energized functionsare not linear, nor are the lines parallel to each other. This meansthat the delta displacement between energized and de-energized states ata given force can be greater than or less than the delta displacement atanother point.

[0027] Now referring to FIG. 2, a delta displacement-force product graphderived from the graph in FIG. 1 is depicted. This graph indicates apeak work value at 40. That is the product of the force times the deltadisplacement is its greatest value at 40 indicating the displacement andforce are peaking.

[0028] Now referring to FIG. 3, a displacement-force graph using thesame data as in FIG. 1 and FIG. 2 is depicted. After looking at FIG. 2,it can be seen that the peak work value is located at 40. A right angletriangle 10 is overlaid on the graph, three line segments are formed AB,BC, CA, where maximum displacement is line segment CA, blocking forceline segment AB, and actuator working line segment BC. The displacementline segment CA is aligned with the peak in work value shown in FIG. 2.This is the point around which a smart material actuator can beoptimally pre-loaded to preferably within at least 40% of the peak workvalue, more preferably to within at least 25% of the peak work value,and most preferably to within at least 10% of the peak work value or theapproximate peak work value itself.

[0029] If the smart material actuator were pre-loaded to 40 units themaximum displacement would be the line segment CA, or 13 units. If thesmart material actuator is energized and the pre-load is increased to 60units, blocking force would be achieved, and the line segment depictingthe displacement to blocking force is segment AB. At this point thesmart material actuator is back to its original height. Since it isimpossible to build a spring with no resistance the line segment CA isimpossible to achieve, so practical design rules prevail and a point onworking segment BC can be used. This point can be optimized to be asclose to the comer of triangle 10 at the intersections of line segmentsCA, BC. It should be noted that triangle 10 can be moved up or downslightly from the peak in work value, graphed in FIG. 2 in order to makesubtle pre-loading optimizations by one skilled in the art. It shouldalso be noted that because of the wide range of materials and geometriesfrom which the actuators are made, each material and geometrycombination can have a different set of graphs requiring each actuatorto be evaluated within its particular application.

[0030] Now referring to FIG. 4, an actual embodiment of a pre-loadmechanism is depicted. Actuator assembly 10 includes a smart materialactuator 20, force transfer member 30, rigid capture ratchet cap 40, andratchet teeth 50. In this embodiment, the compliant mechanism of theactuator assembly 10 is press fit with the ratchet cap structure 40,engaging the ratchet teeth 50, trapping the smart material actuator 20between the force transfer member 30 and ratchet cap structure 40,causing the smart material actuator 20 to be pre-loaded by the amount offorce that the ratchet cap structure 40 is forced against the forcetransfer member 30 and its compliant structure.

[0031] Now referring to FIG. 5a, a second embodiment of the presentinvention is depicted. Actuator assembly 10 includes a smart materialactuator 20, force transfer member 30, floating plate 100, back holdingplate 110, and fastener means 110. In this embodiment, the compliantmechanism of the actuator assembly 10 is held together by the backholding plate 120 with two fasteners 110 trapping the smart materialactuator 20 between the force transfer member 30 and floating plate 100causing the smart material actuator 20 to be pre-loaded by therelationship of the back holding plate 120 to the force transfer member30 and its compliant structure.

[0032] Now referring to FIG. 5b, a close-up view of the floating plate100 is depicted. As the two fasteners 110 are engaged, back plate 110will not move in a parallel fashion to the force transfer member 30. Thesmart material actuator 20 does not tolerate misalignment well.Misalignment can cause a failure of the smart material actuator 20during assembly. Floating plate 100 is designed to allow misalignmentbetween the two surfaces. It accomplishes this by creating a pointcontact with back holding plate 110 and a flat surface with smartmaterial actuator 20.

[0033] Now referring to FIG. 6a, a third embodiment of the presentinvention is depicted. Actuator assembly 10 includes a smart materialactuator 20, force transfer member 30, rigid back plate 40, lower camblock 210, upper cam block 220, and adjustable cam 210. In thisembodiment, the compliant mechanism of the actuator assembly 10 is of asingle one-piece design, with two main features including the rigid rearsupport 40 and force transfer member 30. A second subassembly includingthe cam block assembly 200, 210, 220 is designed as an adjustablespacer. The smart material actuator 20 is captured between the cam blockassembly 200, 210, 220 and force transfer member 30. The cam blockassembly 200, 210, 220 is supported by the rigid rear support 40. As theadjustment cam 210 is moved the dimensions of the adjustable spacerchange, creating greater or less pre-load.

[0034] Now referring to FIG. 6b, an exploded view of the cam blockassembly of FIG. 6a of the present invention is depicted. The lower camblock 200 acts as a bearing for cam screw 210, and upper cam block 220acts as the surface against which the cam screw 210 can act. As the camscrew 210 is rotated the upper cam block moves changing the overalldimension, and creating an adjustable spacer.

[0035] Now referring to FIG. 7a, a cutaway view of a fourth embodimentof the present invention is depicted. The actuator assembly 10 is showncut at about the midpoint, such that the internal features are visible.Actuator assembly 10 includes a smart material actuator 20, forcetransfer member 30, rigid back support 40, lower wedge 300, upper wedge310, and floating plate 100. In this embodiment, the compliant mechanismof the actuator assembly 10 is of a single one-piece design, with twomain features including the rigid rear support 40 and force transfermember 30. A second subassembly including the wedge block assembly 300,310 is designed as an adjustable spacer. The smart material actuator 20is captured between the wedge block assembly 300, 310 and floating plate100. The wedge block assembly 300, 310 is supported by the rigid rearsupport 40. As the wedge assembly 300, 310 is moved with respect to oneanother the dimensions of the adjustable spacer change, creating greateror less pre-load. The smart material actuator 20 does not toleratemisalignment well. Misalignment could cause a failure of the smartmaterial actuator 20 during assembly. Floating plate 100 is designed toallow misalignment between the two surfaces. It accomplishes this bycreating a point contact with back holding plate 110 and a flat surfacewith a smart material actuator 20.

[0036] Referring now to FIG. 7b, a close-up view of the wedge blockassembly 300, 310 of FIG. 7a of the present invention is depicted. Thelower wedge block 300 and upper wedge block 310 act as an adjustablespacer. As the upper and lower wedges 300 are driven together the spacerincreases in dimension and as the upper and lower wedges are driven awayfrom one another the spacer decreases in dimension. The wedges are heldin place with a toothed arrangement. In this manner, an adjustablespacer is created.

[0037] Referring now to FIG. 8, a cutaway view of a fifth embodiment ofthe present invention is presented. The actuator assembly 10 is showncut at about the midpoint such that the internal features are visible.Actuator assembly 10 includes a smart material actuator 20, forcetransfer member 30, rigid back support 40, ring spacer 410, ringadjustment screw 400, and floating plate 100. In this embodiment, thecompliant mechanism of the actuator assembly 10 is of a single one-piecedesign, with two main features including the rigid rear support 40 andforce transfer member 30. A second subassembly, the adjustable ringspacer assembly 400, 410 can be designed as an adjustable spacer. Thesmart material actuator 20 can be captured between the adjustable ringspacer assembly 400, 410, and floating plate 100. The adjustable ringspacer assembly 400, 410 can be supported by the rigid rear support 40.As the ring adjustment screw 400 is rotated, the dimensions of theadjustable spacer change, creating greater or less pre-load. The smartmaterial actuator 20 does not tolerate misalignment well. Misalignmentcould cause a failure of the smart material actuator 20 during assembly.Floating plate 100 is designed to allow misalignment between the twosurfaces. It accomplishes this by creating a point contact with backholding plate 110 and a flat surface with smart material actuator 20.

[0038] Referring now to FIG. 9, a cutaway view of a sixth embodiment ofthe present invention is depicted. The actuator assembly 10 is shown cutat about the midpoint such that the internal features are visible.Actuator assembly 10 includes of a smart material actuator 20, forcetransfer member 30, rigid back support 40, lower semicircle wedge 520,upper semicircle wedge 540, center wedge 530, wedge adjustment screw510, and upper and lower bearings 500, 540. In this embodiment, thecompliant mechanism of the actuator assembly 10 is of a single one-piecedesign, with two main features including the rigid rear support 40 andforce transfer member 30. A second subassembly, the adjustable wedgeassembly 500, 510, 520, 530, 540, 550 can be designed as an adjustablespacer. The smart material actuator 20 can be captured between theadjustable wedge assembly 500, 510, 520, 530, 540, 550. The adjustablewedge assembly 500, 510, 520, 530, 540, 550 can be supported by therigid rear support 40. As the wedge adjustment screw 510 is rotated, thedimensions of the adjustable spacer change, creating greater or lesspre-load. Bearing blocks 500, 540 can provide a surface for the upperand lower semicircle wedges to rotate. Upper and lower semicircle wedges500, 540 have a second bearing surface that can interface with thecenter wedge 530 as the center wedge 530 is drawn toward the head of thewedge adjustment screw 510 driving the upper and lower semicircle wedgesaway from each other driving upper and lower bearing blocks creatingmore pre-load. As the center wedge 530 is drawn away from the head ofthe wedge adjustment screw 510, driving the upper and lower semicirclewedges towards each other, driving upper and lower bearing blocks, andcreating less pre-load.

[0039] Now referring to FIG. 10, a seventh embodiment of the presentinvention is depicted. Actuator assembly 10 includes a smart materialactuator 20, force transfer member 30, rigid back plate 40, pre-loadscrew 600, and floating plate 100. In this embodiment, the compliantmechanism of the actuator assembly 10 is of a single one-piece design,with two main features including the rigid rear support 40 and forcetransfer member 30. The pre-load screw 100 can be supported by the rigidback plate 40, and the floating plate 100 can be positioned betweensmart material actuator 20 and pre-load screw 600. Pre-load screw 600can be threaded and as the screw rotates it can act as an adjustablespacer. As the pre-load screw 600 rotates, such that additional force isapplied to the smart material actuator 20, the pre-load value isincreasing or greater, and as the screw rotates such that force is beingremoved from the smart material actuator 20, the pre-load value isdecreasing or less. The smart material actuator 20 does not toleratemisalignment well. Misalignment can cause a failure of the smartmaterial actuator 20 during assembly. Floating plate 100 is designed toallow misalignment between the two surfaces. It accomplishes this bycreating a point contact with the pre-load screw 600 and a flat surfacewith smart material actuator 20.

[0040] While the invention has been described in conjunction with whatare presently considered to be the most practical and preferredembodiments, it is to be understood that the invention is not to belimited to the disclosed embodiments but, on the contrary, it isintended to cover various modifications and equivalent arrangementincluded within the spirit and scope of the appended claims, which scopeis to be accorded the broadest interpretation so as to encompass allsuch modifications and equivalent structures as permitted under law.

What is claimed is:
 1. An apparatus comprising: a support structuredefining a rigid non-flexing portion and a movable portion; a smartmaterial actuator for driving the movable portion of the supportstructure between first and second positions; and means for preloadingthe smart material actuator with a sufficient preload force to optimizework output of the support structure, where work output is defined as afunction of displacement and force with infinite life of the supportstructure.
 2. The apparatus of claim 1, wherein the preloading meansoptimizes work output to an efficiency of between approximately 60% toapproximately 90%, inclusive of the work input from the smart materialactuator.
 3. The apparatus of claim 1, wherein the preloading meansoptimizes work output to an efficiency of greater than 60%, inclusive ofthe work input from the smart material actuator.
 4. The apparatus ofclaim 1, wherein the preloading means optimizes work output to anefficiency of between approximately 75% to approximately 90%, inclusiveof the work input from the smart material actuator.
 5. The apparatus ofclaim 1, wherein the preloading means optimizes work output to anefficiency of greater than 75%, inclusive of the work input from thesmart material actuator.
 6. The apparatus of claim 1, wherein thepreloading means optimizes work output to an efficiency of greater than90%, inclusive of the work input from the smart material actuator. 7.The apparatus of claim 1, wherein the preloading means optimizes workoutput to within 20% of peak load as determined by the forcedisplacement product versus force curve of the work input from the smartmaterial actuator.
 8. The apparatus of claim 1, wherein the preloadingmeans is located between the rigid, non-flexing portion of the supportstructure and the smart material actuator.
 9. The apparatus of claim 8,wherein the preloading means further comprises: an adjustable threadedscrew extending between the rigid, non-flexing portion of the supportstructure and one end of the smart material actuator.
 10. The apparatusof claim 8, wherein the preloading means further comprises: anadjustable wedge positioned between the rigid, non-flexing portion ofthe support structure and one end of the smart material actuator. 11.The apparatus of claim 10, wherein the adjustable wedge furthercomprises: a first semi-circular wedge portion, a second complementarysemi-circular wedge portion, a center wedge portion, and an adjustmentscrew, such that adjustment of the screw moves the center wedge portionwith respect to the first and second semi-circular wedge portions towardand away from one another and adjusts an amount of preload applied tothe smart material actuator.
 12. The apparatus of claim 10, wherein theadjustable wedge further comprises: a first longitudinal wedge portionengageable with the rigid, non-flexing portion of the support structureand a second longitudinal wedge portion engageable with one end of thesmart material actuator, the first wedge portion having a transverselyextending, angled, serrated surface and the second wedge portion havinga complementary transversely extending, angled, serrated surface foroperable interlocking engagement with the first wedge portion, such thattransverse movement of one wedge portion with respect to the other wedgeportion adjusts an amount of preload applied to the smart materialactuator.
 13. The apparatus of claim 10, wherein the adjustable wedgefurther comprises: a first cam surface portion, a second complementarycam surface portion, a cam screw located between the first and secondcam surface portions, such that adjustment of the cam screw moves thecam surface portions with respect to the one another and adjusts anamount of preload applied to the smart material actuator.
 14. Theapparatus of claim 8, wherein the preloading means is located betweenthe rigid, non-flexing portion of the support structure and the moveableportion of the support structure.
 15. The apparatus of claim 14, whereinthe preloading means further comprises: the rigid, non-flexing portionof the support structure having a separable, adjustable, rigid,non-flexing web operably engageable with at least one rigid, non-flexingarm of the support structure, such that the adjustment of the web withrespect to the at least one arm allows locking engagement between theweb and the at least one arm of the support structure at a predeterminedpreload on the smart material actuator.
 16. The apparatus of claim 15,wherein the preloading means further comprises: the web having a firstserrated portion engageable with a complementary second serrated portionformed on the at least one arm for operable interlocking engagement withone another, such that movement of web with respect to the at least onearm adjusts an amount of preload applied to the smart material actuator.17. The apparatus of claim 15, wherein the preloading means furthercomprises: the web having at least one adjustable screw operablyengageable within at least one corresponding threaded aperture formed inthe at least one arm for operable interlocking engagement with oneanother, such that adjustment of the screw causes movement of web withrespect to the at least one arm and applies preload to the smartmaterial actuator.
 18. The apparatus of claim 1, wherein the smartmaterial actuator is a piezoelectric actuator.
 19. A process foroptimizing preload of a smart material actuator for driving a movableportion of a support structure between first and second positionscomprising the steps of: measuring deflection of support structureversus force applied during energization and deenergization of a smartmaterial actuator over a predetermined range of force; evaluating forcedisplacement product versus force to determine a peak value for forcedisplacement product; and preloading the smart material actuator to avalue at least within 40% of the peak value for force displacementproduct.
 20. The process of claim 19, wherein the preloading stepfurther comprises preloading the smart material actuator to a value atleast within 25% of the peak value for force displacement product. 21.The process of claim 19, wherein the preloading step further comprisespreloading the smart material actuator to a value at least within 10% ofthe peak value for force displacement product.
 22. The process of claim19, wherein the preloading step further comprises preloading the smartmaterial actuator to the peak value for force displacement product. 23.A product manufactured according to the process of claim 19 furthercomprising: a support structure defining a rigid non-flexing portion anda movable portion; a smart material actuator for driving the movableportion of the support structure between first and second positions; andmeans for preloading the smart material actuator with a sufficientpreload force to optimize work output of the support structure, wherework output is defined as a function of displacement and force withinfinite life of the support structure.
 24. The product of claim 23,wherein the preloading means optimizes work output to an efficiency ofbetween approximately 60% to approximately 90%, inclusive of the workinput from the smart material actuator.
 25. The product of claim 23,wherein the preloading means optimizes work output to an efficiency ofgreater than 60%, inclusive of the work input from the smart materialactuator.
 26. The product of claim 23, wherein the preloading meansoptimizes work output to an efficiency of between approximately 75% toapproximately 90%, inclusive of the work input from the smart materialactuator.
 27. The product of claim 23, wherein the preloading meansoptimizes work output to an efficiency of greater than 75%, inclusive ofthe work input from the smart material actuator.
 28. The product ofclaim 23, wherein the preloading means optimizes work output to anefficiency of greater than 90%, inclusive of the work input from thesmart material actuator.
 29. The product of claim 23, wherein thepreloading means optimizes work output to within 20% of peak load asdetermined by the force displacement product versus force curve of thework input from the smart material actuator.
 30. The product of claim23, wherein the preloading means is located between the rigid,non-flexing portion of the support structure and the smart materialactuator.
 31. The product of claim 30, wherein the preloading meansfurther comprises: an adjustable threaded screw extending between therigid, non-flexing portion of the support structure and one end of thesmart material actuator.
 32. The product of claim 30, wherein thepreloading means further comprises: an adjustable wedge positionedbetween the rigid, non-flexing portion of the support structure and oneend of the smart material actuator.
 33. The product of claim 32, whereinthe adjustable wedge further comprises: a first semi-circular wedgeportion, a second complementary semi-circular wedge portion, a centerwedge portion, and an adjustment screw, such that adjustment of thescrew moves the center wedge portion with respect to the first andsecond semi-circular wedge portions toward and away from one another andadjusts an amount of preload applied to the smart material actuator. 34.The product of claim 32, wherein the adjustable wedge further comprises:a first longitudinal wedge portion engageable with the rigid,non-flexing portion of the support structure and a second longitudinalwedge portion engageable with one end of the smart material actuator,the first wedge portion having a transversely extending, angled,serrated surface and the second wedge portion having a complementarytransversely extending, angled, serrated surface for operableinterlocking engagement with the first wedge portion, such thattransverse movement of one wedge portion with respect to the other wedgeportion adjusts an amount of preload applied to the smart materialactuator.
 35. The product of claim 32, wherein the adjustable wedgefurther comprises: a first cam surface portion, a second complementarycam surface portion, a cam screw located between the first and secondcam surface portions, such that adjustment of the cam screw moves thecam surface portions with respect to the one another and adjusts anamount of preload applied to the smart material actuator.
 36. Theproduct of claim 30, wherein the preloading means is located between therigid, non-flexing portion of the support structure and the moveableportion of the support structure.
 37. The product of claim 36, whereinthe preloading means further comprises: the rigid, non-flexing portionof the support structure having a separable, adjustable, rigid,non-flexing web operably engageable with at least one rigid, non-flexingarm of the support structure, such that the adjustment of the web withrespect to the at least one arm allows locking engagement between theweb and the at least one arm of the support structure at a predeterminedpreload on the smart material actuator.
 38. The product of claim 37,wherein the preloading means further comprises: the web having a firstserrated portion engageable with a complementary second serrated portionformed on the at least one arm for operable interlocking engagement withone another, such that movement of web with respect to the at least onearm adjusts an amount of preload applied to the smart material actuator.39. The product of claim 37, wherein the preloading means furthercomprises: the web having at least one adjustable screw operablyengageable within at least one corresponding threaded aperture formed inthe at least one arm for operable interlocking engagement with oneanother, such that adjustment of the screw causes movement of web withrespect to the at least one arm and applies preload to the smartmaterial actuator.
 40. The product of claim 23, wherein the smartmaterial actuator is a piezoelectric actuator.